Dear Bloggers, Invitro dissolution test means the rate and extent of dissolution i.e. amount of drug dissolves in the medium. A dissolution study of dosage form necessities modification in dissolution medium to increase solubility. Since pH of GIT is 1-8 it is necessary to develop the medium where the drug has maximum solubility and exhibits sink condition. The ratio of solubility to drug concentration expressed as cs/cd represents the closeness to the sink condition. A sink condition occurs when the drug that can be dissolved in the dissolution medium is 6 times greater than the amount of drug to be dissolved. Thus solubility study is carried out and the media in which maximum solubility occurs is selected. A discriminative dissolution method has to be developed to exhibit different results when the manufacture of a product changes. Discrimination in dissolution having dissolution test which will show a difference between one formulation and another. A discriminating medium is one part of discriminating dissolution test. The media should be able to meet sink condition. To determine a good media typically it is but to select study several different pH media, rpm. The dissolution method should be sensitive to variation that can be an impact on the invivo performance of the dosage form. Discriminative method is found to be promising tool for the new drug in the selection of better medium based upon its physico-chemical nature with respect to the body condition.